In the midst of studies conducted concerning the storage technique in the next generation, the hologram recording technique in which digital information (info) is recorded utilizing the holography is attracting attention.
The hologram recording technique is a technique of superposing a signal beam having information of page data modulated two-dimensionally by a spatial light modulator on a reference (ref) beam within recording media, causing refractive index modulation in the recording media by using an interference fringe pattern generated at that time, and thereby recording information. When reproducing information, the recording media is irradiated with the reference beam used at the time of recording in the same arrangement and consequently a hologram recorded in the recording media acts like a diffraction grating and generates a diffracted beam. This diffracted beam is reproduced as the same beam as the recorded signal beam inclusive of phase information.
The reproduced signal beam is detected fast two-dimensionally by using photodetectors such as CMOSs or CCDs. In such hologram recording, two-dimensional information is recorded/reproduced simultaneously by using one hologram and a plurality of page data can be written in superposition on the same place. Therefore, such hologram recording is effective for fast recording and reproducing of a large capacity of information.
JP-A-2009-87447 (Patent Literature 1) describes “after data is recorded, data is verified as occasion demands (S27), and post cure is conducted by using an optical beam emitted from a disk cure optical system 13 (S28)”.